[TLS] TLS extensions in ServerHello
Axel.Heider@gi-de.com Mon, 16 July 2007 13:46 UTC
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Subject: [TLS] TLS extensions in ServerHello
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Hello, currently, the TLS 1.2 draft says about the server_hello_extension_list: "A list of extensions. Note that only extensions offered by the client can appear in the server's list.". And for the client_hello_extension_list is says "Clients MAY request extended functionality from servers by sending data in the client_hello_extension_list." As a consequnece, it is impossible for a server to e.g. tell a client to set certain things, if the client did not offer them before. In my case I have a server with very limited resources and a client running on a normal PC with almost no limitations. So the client will usually not send a max_fragemnt_length extension, because it does not really care about this. However, my server cares, but there is no way for it to tell this to the client. Should the spec force the clients to send a list of all supported extensions? Should the server be allowed to send anything in its server_hello_extension_list, if the client said it supports TLS1.2? And if so, how does the client confirm it accepted the extensions send by the server? --- Mit freundlichen Grüssen / Best regards Axel Heider NB4, Research and Development / Division New Business Giesecke & Devrient GmbH, Prinzregentenstrasse 159, 81677 München, Germany Tel.: +49-(0)89-4119-2693, E-Mail: axel.heider[at]gi-de.com , http://www.gi-de.com Creating Confidence. -------------------------------------------------------------- Vorsitzender des Aufsichtsrats: Dr. Peter Mihatsch Geschäftsführer: Dr. Karsten Ottenberg (Vorsitzender, CEO), Michael Kuemmerle, Hans Wolfgang Kunz, Dr. Walter Schlebusch, Dr. Peter Zattler (CFO) Gesellschaftssitz: München, Handelsregister Amtsgericht München HRB 4619. _______________________________________________ TLS mailing list TLS@lists.ietf.org https://www1.ietf.org/mailman/listinfo/tls
- [TLS] TLS extensions in ServerHello Axel.Heider
- RE: [TLS] TLS extensions in ServerHello Mark Brown